Practical Hypermedia: An Introduction to HyTime. Kimber, William E.. Prentice-Hall Professional Technical Reference. ISBN 0-13-309899-0. Draft available for review. Due
to be published mid 1998. URL: http://www.drmacro.com/bookrev

This paper has tried to provide a brief but informative introduction
to the SGML architecture mechanism, how it is used with documents, and how
processors can take advantage of architectures. I have not explored all the
details of the architecture mechanism nor have I plumbed the depths of esoteric
subtlties such as fine control of archictural mapping and unmapping. It is
not necessary to understand any of these details in order to make immediate,
productive use of architectures.

For most uses of architectures, simple mappings that rely heavily on
the automapping mechanism will be the order of the day and will meet most
requirements. In particular, the use of what would otherwise be document-level
DTDs as architectures can provide significant benefits for "DTD-less" documents
at a minimum cost, letting document creators enable validation without burdening
instances with otherwise unnecessary DTD declarations.

Finally, when thinking about the SGML architecture mechanism, keep two
important things in mind. First, the DTD declaration part of architectures
is only part of the whole picture. An architecture is always bigger than the
SGML-defined declarations used for it, so you should expect to have (or provide)
additional definitions and documentation for the architectures you are using,
including prose descriptions as well as other formal specifications, such
as object models or database schemas. No useful architecture can be completely
defined by DTD declarations alone.

Second, remember that an architecture is, ultimately, a bag of rules
that you can give a universally-unique name to. The public ID or URN you give
to an architecture names the entire set of rules, however they might be defined,
not just the SGML-syntax formalisms. This provides a way for documents to
point unambiguously to the rules that govern them. This pointing to the rules
makes it clear to both human observers and processing programs what the intended
rules are without the need to pass that information "out of band". This alone
can have as much benefit as facilities like architectural validation and name
remapping provide.

Practical Hypermedia: An Introduction to HyTime. Kimber, William E.. Prentice-Hall Professional Technical Reference. ISBN 0-13-309899-0. Draft available for review. Due
to be published mid 1998. URL: http://www.drmacro.com/bookrev